Treatment of paper



Patented 7 Mar. 30, 1937 UNITED STATES TREATMENT OF PAPER James Augustus Arvin, Wilmington, DeL, assignorto E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 3, 1934. Serial No. 713,945

5 Claims.

This invention relates to the art of water-proofing and sizing of porous bodies, and more particularly to the treatment of paper products.

In my co-pending application Serial No. 651,634

5 filed January 13, 1933, of which this application is a continuation in part, I have disclosed and claimed new synthetic resins and have also disclosed the manufacture of water-proof materials by the treatment of fabrics, paper, etc. with these resins. The present invention is concerned specifically with the products obtained by the impregnation, coating, sizing, glazing or waterproofing of porous materials, and particularly to the treatment of paper for these purposes.

of new and useful paper products. A further object is the production of new and useful water proofed papers. A further object .is the production of paper products which are chemically inert, transparent, water-resistant, oil'and grease-proof, and which have markedly improved wet and dry strength.

These objects are accomplished by the treatment of paper in the manner specifically disclosed hereinafter with synthetic resins of the type described in the above identified application.

These synthetic resins are the reaction products of substantially unpolymeriaable monomeric polyhydric phenols and polyhalides whose halogen atoms are attached toaliphatic carbon atoms. The halides are organic compounds having at least two carbon atoms and at least two reactive halogen atoms, the latter all being attached to different carbon atoms. The latter carbons must be 35 joined to other atoms by single bonds only. The resins are best made by condensing the alkali or alkaline earth metal of the polyhydric phenol with the polyhalide.

The following is the preferred general method 40 for making these resins: The polyhydric phenol is mixed with an aqueous solution of the theoretical or a slightly excess quantity of alkali and heated at a relatively high temperature, above 70 C. and preferably above 100 C., but below the 45 decomposition temperatures of the ingredients.

with a chemically equivalent amount of the polyhalide. The apparatus preferably consists of a vessel fitted with a thermometer, refiux condenser,

55 sample becomes essentially constant; where the This invention has as an object the manufacture theoretical amount of alkali was used originally, the final product is nearly neutral. (This method of following the progress of the resinification, however, is sometimes only approximate since part of the alkali may be used up in the hydrolysis of the polyhalide, a side reaction which does not contribute to the resinification.) Tests can be made for uncombined halide by distilling a few drops from the reaction vessel (when the halide is volatile). If this distillate is cloudy, some of the halide is uncombined and refluxing is continued. .When the distillate is clear, the water can be distilled off without loss of halide; this will then permit the use of higher temperatures inthe later stages of the reaction with a resultant decrease in time of preparation. Further heating after the distillate becomes clear is generally necessary, inasmuch as this clear point only shows that essentially all'the halide has been combined by the elimination of at least one of its halogen atoms, but not necessarily all of them. I'he final reaction mass is very viscous; also opaque because of occluded salt. When it has reached the desired consistency, the hot mass is poured into a steamjacketed Werner-Pfieiderer'Z type mixer and washed with small portions of dilute hydrochloric acid and finally with waterito remove the salt. The resin is then dried, either in vacuo or at atmospheric pressure, for several hours at temperatures above its melting point, e. g., in the range 100-150 C. Clear tough resins are obtained whose hardness will depend largely on the temperature, timeof reaction, and certain other details.

A resin useful in the practice of this invention may be made as indicated below:

Parts Di (4-hydroxyphenyl) dimethylmethane (M. P.

157" C.) 456 Dichlorodiethyl ether 286 Water 450 Sodium hydroxide (50%) 326 The above mixture is refluxed in an atmosphere of nitrogen or water vapor for 10-15 hours with stirring or until a few drops of clear distillate shows that there is no remaining free halide. The' water is distilled ofi over a period of two hours, the temperature finally being carried to 225'230 C. and maintained at this point for 12 hours. The mass is now very viscous and pasty. It is poured while hot into a steamjacketed Werner-Pfieiderer mixer, washed three times with water, then with small portions of dilute hydrochloric acid until the washings are 5 resin is hard, clear, pale-colored and extremely tough, and is inert to acid, alkali, water and light. It is insoluble in alcohol and aliphatic hydrocarbons, but -soluble in toluol, xylol and aromatic esters such as dibutyl phthalate. Films dry to a hard, non-tacky condition in a very few minutes by simple evaporation of solvent; in this respect, the resin resembles cellulose derivatives. The resin does not mix readily with oils and most cellulose derivatives, but is compatible with benzyl cellulose. The resin does not heat-harden (like a phenol-formaldehyde resin)= nor dry by oxidation (like a drying oil modified polyhydric alcohol-polybasic acid resin).

Other resins which are particularly suitable for the manufacture of my improved paper products are the following resins prepared from the following ingredients in the manner indicated.

above:

Di (3-methyl-4-hydroxyphenyl) dimethylmeth-- ane and ethylene dichloride. I 1,1-di(4-hydroxyphenyl) *cyclohexane and p,p'-

dichlordiethyl ether.

Di-p-naphthol and p,fl'-dichlorodiethyl ether. Di- (4hydroxyphenyl) naphthane-2 and p,p dichlordiethyl ether.

Di(4-hydroxynaphthyl)dimethylmethane and 5,5 dichlorodiethyl ether.

In carrying out the present invention the paper is treated with a polyether resin of the kind described above in the form of solutions in organic solvents, aqueous dispersions of the resin or solutions thereof, or hot melts. By the term treatment as I use it herein, I mean any process for applying the polyether type resin to thepaper,

40 such assizing, coating, and impregnation processes 'known to the art. In the practice of the invention I generally prefer to treat the paper with a solution of the polyether resin in an organic solvent by the. process known to the art as tub sizing. The amount of polyether resin to be deposited on the paper is determined'to a large extent by the purpose to which the product is tobe put and therefore varies within wide limits. The concentration of the polyether resin solution also varies within wide limits. In order to get products having the greatest degree of oil, water, and grease-proofness, it is necessary to treat the paper with a sufficient amount of the polyether resin to give a continuous surface film. The absorbency 01' the paper determines the amount of resin required to give a continuous surface film; thus, highly absorbent papers require a larger quantity of the polyether resin than less absorbent papers, as for example, 0 glassine paper, parchmentized papers, or papers formed from very highly hydrated stocks. Instead of using solutions in organic solvents: for the treatment of the paper, I may to equal advantage use aqueous dispersions of the resins 5 and after the treatment remove the water by drying at elevated temperature. Aqueous emulsions of solutions of the resins in organic solvents may likewise be used.

In general, paper treated by the tub sizing '70 process described above has improved properties with respecttowater resistance and wet and dry strength, irrespective of whether the amount of resin deposited on the paper is large or small. However, I generally prefer to saturate the sheet 75 with the polyether resimbecause under these aomsss conditions I get products having the desired water-resistance, transparency, oil and greaseproofness, etc. However, the use of too much of the resin detracts from the flexibility and. the amount used must be properly balanced against flexibility requirements.

. If it-is desired to coat the paper with the resin without obtaining substantial penetration thereof, I prefer to use the so-called "hot melt process. In this process, the resin is fused, spread on the paper, excess resin removed with a hot doctor knife or with a heated roll, and the treated product allowed to cool to room temperof ,the invention for the preparation of products that are-to be used in applications requiring. extreme oil, gasoline, and water resistance, but in which pliability is not a primary requirement. A resin particularly suitable in this method is the polyether resin obtainable by the reaction of di (3-methyl-4-hydroxyphenyl)dimethylmethane and p,p-dichlordiethyl ether in the presence of alkali. w

As an alternative. but less desirable process, I may employ the process known to the trade as beatersizing". In the beater sizing process the pulp is beaten ina paper beater until it is nearly ready to form into a sheet on any standard type of machine. The polyether resin in the form of an aqueous emulsion is then added to the beater,and the beating continued for a sufficient length of time to disperse the emulsion intimately into the pulp. Any of the common size precipitants, as for example, alum, is then added to bring about deposition of the polyether resin in finely divided form on the surface of the fibers. The amount of polyether resin to be incorporated into the pulp varieswithin wide limits, depending upon the purpose to which the paper is to be put.

The aqueous emulsions of the polyether resins may be prepared by any method known to the A sheet of unbeaten kraft paper was drawn through a 1.5% toluene solution of the polyether resin, prepared by the reaction of di(4- hydroxyphenyl) dimethylmethane and fi.fi'-di- 1 chlor diethyl ether in the presence of alkali, then through squeeze rolls to remove excess resin solution from the surface of the paper, and the treatedpaper dried at loo-110 C. The polyether resin content of the impregnated paper was 2%, based on the dry weight of the fiber.

The water resistance of the sheet, measured by the dry indicator method, was increased from 0 seconds to seconds by application of the" resin. The Mullen bursting'strength of the dry sheet was'increased from 21.4 to 27 and of the used for the impregnation of the pulp was'prere ew:

aomssa To 241 grams of a solution of the following composition:

- Grams 10% casein in tri-sodium phosphate solu-j was added in a colloid mill 'l2 grams 01's. 33%% toluene solution of the polyether resin obtain-' able by the reaction of di(3'methy1 4ihydrxy- 1 through the alkali salt of the phenolor some other phenyl) dimethylmethane and p,p'-dichlordiethyl ether in the presence of alkali, and the mixture circulated through the colloid mill for 4 minutes. The resulting dispersion was stable and had average particle size of 4 microns.

A beater was charged with a high alpha cellulose content wood pulp, and the pulp beaten until sufficiently hydrated for sheet formation.

To the pulp was then added the polyether resin emulsion described above in an amount equal to 2%, based on the weight of the fiber, and the mixture beaten until the emulsion and the pulp were intimately mixed. Alum was then added until the pulp had a pH of 4.8. Sheets were then formed by means of a hand mold',-press'ed between wool felts, and'dried. 1

The waterfresistance of the paper formed as.

described above, measured by' the dry indicator method, was 50.7 as compared toflforth'euntreat ed paper. The Mullen bursting strength of the dry sheet was increased from 21.4 to 23,,andof the wet sheet from 2.6 to 5. f

-E:cample III i A sheet of high grade rag paper was drawnthrough a bath containing a- 1.5% toluenesolution of the polyether resin obtained by the re-'- action of dli4-hydroxyphenyl)dimethylmethane and B,fi'-dichlordiethyl ether inth'e presence of- I alkali, then through squeeze rolls to remove excess solution from the surface of the paper, and

the sheet dried at room temperature. The 'treat ed product was markedly superior to the untreated paper in respect to wrinkling, crumpling,

and tearing resistance, and also in respect to water, gasoline, and oil-proofness.

Example IV A sheet of high grade cotton paper was coated Example V A sheet of tissue paper was drawn through a bath of the solution of the polyether resin of Example III, then through squeeze rolls to remove the sheet dried at 100-110 C. The product obtained was transparent, and had very markedly improved tear, water, oil, and gasoline resistance.

The several methods of making the resins, and i any of the ether resins disclosed in my co-pendthe practice of this invention. Thus, some of the useful phenols for making the resin, other than those mentioned above, include resorcinol, catei chol, P,P'-dihydroxydiphenyl, dihydroxynaphdrolysis.

excess solution from the surface of the paper, and

ing application referred to above may be used in' thalenes, di (4-hydroxylphenyl) phenylmethane,

. di (4-hydroxy- 3 -chlorophenyl) dimethylmetlianc,

di(4-hydroxyphenyl) sulfone and sulfide, etc.'

Various polyhalides in addition to or instead of those mentioned'may likewise be used to make' the resin.

mide, propylene dichloride, glycer01 -a,-;dich1or- .hydrin,-hexamethylene dibromide, etc. Bromides Among these are wi'dichlorodipropyl- .ether, l,4-,dichlorocyclohexane, 1,4,7-trichloro- .heptane, dichlorodiethylamine, xylylene dibro-' and iodides are in many casesrnore active than a the chlorides but are less-economical. Apparently the only requisite is that the halogen atoms be sufiiciently reactive to combine with the' phenol,

common method for making et hers. It is a weli known. factof chemistry that there are definite types of halogen atoms which are not readily-hydouble bond, an illustration being the chlor ine V at0ms ofyinyl chloride and the halogen atoms attached .to aromatic nuclei. Reactive halogen atoms,;as the term isused'hereinaretherefore those which are attachedtocarbonatoms which in turn are joined to other atomsbymeans of only single bonds, Only po yhalides having two or r morecarbons are operable forfmaking the polyether,resins. The halogen atoms arefp 'eferably attached to different carbons to, avoid the 1 mationof acetol -like structures which, although of the ether-type, are moreisusceptible qhyg By polyhydrlc phenol, as used in the present I specification and claims, is meant'a phenolic body having at least two phenolic "hydrox'yls, the phenolic body being substantially unpol'ymeriza ble in that it is not readily converted on heat treatment to aninfusible or insoluble product.

. Theresins mentioned above are, as disclosed in my cog-pending application Serial No. 651,634 filed January. l3, 1933, ether resins'whichmay be de,-

, finedstructurally. as having'a recurrence of the gro ping where X is a bivalent organic radical having its'freevalences directly attached toaromatic carbon atoms, 0 is oxygen,

and Y is a bivalent organic radical having its free valences. directly attached to singly bonded, non aromatic carbon atoms. X may be an aryl group or it may have other substituents or components.-

The preferred resins obtained from dihydric phenols and dihalides may be formulated thus: X--O -Y-OX O"Y-'O-'-X -'-O Y--O and apparently contain substantially all of the structural units iii-linear chains. The

resins are extremely resistant to chemical action including that of strong acids and alkalis. However, on very dra's tic treatment with strong hydrobromlc orh'ydroiodic acids, such as long-continued boiling, the aromatic ether linkages can be split, although with dlfiiculty, and a mixture of products comprising a polyhydric phenol and toluene, xylene, and-the like. If desired, however,

the aromatic hydrocarbon may be substituted in part by solvents such as aliphatic hydrocarbons, chlorinated hydrocarbons, and esters.

Any form of paper such as glassine, wrapping paper, high grade rag or linen paper,- or any of the special highly porous absorbent papers used for impregnation may be employed in the practice of this invention.

The solutions of the polyether resins may vary in concentration within wide limits. depending both upon the methodto be used in the treat-' ment of the paper and the absorbency of the paper to be treated. For purposes of impregnation, I generally prefer to use dilute solutions, that is, solutions varying in. concentration up to 20 to 25%, preferably not more than 5%. On the other hand, for purposes of coating, I prefer to a use concentrated. solutions, that is, varying'up to 50 or 60% solids. In'thecase of certain"of'the polyether resins, such as those obtainable by reaction of di(3-methyl 4 hydroxyphenyDdimethylmethane and p,p'-dichlordiethyl ether in the presence of alkali, products that are pliable, transparent, and highly moisture, grease. and oilresistant canbe obtained by application oi the resin to the paper in the form of a hot'melt.

The polyether resins used in the manufactureof the products of this invention may be combined with such materials as natural resins, as 40 for example, rosin, congo, damar, and the like; natural resin acid esters, such as, ester gum; chlorinated naphthalenes, such as Halowaxes; chlorinated diphenyis; rubber; and various hydrogenated products such as hydrogenated rubber, hydrogenated rosin, and-hydrogenated ester gum. Papers treated with the' polyether resin in combination with hydrogenated resins have'improved resistance to the deteriorating action of light. I

The treated paper products of this invention are highly useful inthe manufacture of waterproof and oil-proof containers, milk caps, shot shells, transparent wrapping paper. currency aomass paper, washable wall paper, paper for electrical insulation, bookbinding material, etc.

A valuable pro y of my impregnated paper products is their transparency, a highly desirable property in. paper not conferred by synthetic resins in general. Other outstanding and very desirable characteristics of the impregnated 'productsis their high water-resistance, oil, and

grease-proofness, pliabiiity, markedly improved wet and, dry strength, chemical inertness, and

permanence of color.

As many apparently widely diiferent embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim: v

1. As a new article of manufacture paper treated with the resinousreaction product of a substantially unpolymerizable polyhydric phenol 'and an .organic polyhalide whose halogen atoms 1 are all attached to different carbon atoms, said carbon atoms being Joined to other atoms by single bonds only.

2. As a new article of manufacture water-.

proof paper having a surface film of the resinous reaction product of a substantially. unp'olymerizable polyhyd'ricphenol and an organic pclyhalide whose halogen atoms are all attached to diiferent carbon atoms, said carbon atomsbeing joined to other atoms by single bonds only.

3. As a new article of manufacture paper treated with av synthetic resin giving on long continued hydrolysis with hot hydrobromic acid,

at least one substantiallyunpolymerizable polyhydric phenol and one organic polyhalide whose halogen atoms are all attached to different carbon atoms. said carbon atoms being Joined to 6,

other atoms by single bonds only.

4. As a new article of manufacture paper impregnated throughout with the resinous reaction productvof a substantially unpolymerisable' monomeric polyhydric phenol and an organic polyhalide whose halogen atoms are all attached to diflerent carbon atoms, said carbon atoms being joined to other atoms by single bonds only.

5. As a new article of manufacture, paper treated with the resinous reaction product of fl,fl'-dichlorodiethyl ether and di-(i-hydroxyphenyl) dimethylmetliane. 1

James auous'rns ARVIN. 

